Eruptions of the Yellowstone volcanic system have included the two largest volcanic eruptions in North America in the past few million years; the third largest was at Long Valley in California and produced the Bishop ash bed.
On the diesel Passat, the TDI badge stands for Turbocharged Direct Injection, which isn't really all that helpful as the gasoline-powered Passat is also turbocharged and also uses direct injection. Volkswagen attempts to clear this up by calling this Passat the Passat TDI Clean Diesel.
The SDI engine is a design of naturally aspirated (NA) direct injection diesel engine developed and produced by Volkswagen Group for use in cars and vans, along with marine engine (Volkswagen Marine) and Volkswagen Industrial Motor applications.he SDI engine is generally utilised in applications where reliability and fuel economy are of primary concern. These engines lack any type of forced induction, hence the use of 'suction' in the title, and as such, their power output is lower when compared with a similar displacement turbocharged engine.